This invention relates to holding devices for holding an individual container, while such container is being filled, cleaned or tested for example, and more particularly to a novel holding device and method for accommodating individual containers of different size.
Before a container, such as an aerosol can, is filled and sealed, it is normally subjected to a cleaning process and a pressure or leak test to ensure that the container meets specified requirements for cleanliness, strength and leak resistance. Cleaning, pressure and leak testing are usually accomplished automatically by continuously transporting a succession of containers on a conveyor belt past a series of processing stations.
Since most aerosol containers are formed of non-ferrous materials, a well-known, convenient way of securing each container to a conveyor belt is through the use of a container holding device that releasably grips the container and is magnetically held on the conveyor belt.
One known holding device, disclosed in U.S. Pat. No. 3,941,237, comprises a plastic puck with interior fins integrally molded with the wall of the puck. Engagement of the plastic fins with the periphery of a container that is receivable in the puck releasably holds the container in the puck. A magnetic ring secured to the base of the puck retains the puck on a corresponding magnetic portion of a conveyor belt.
It has been found that the puck of U.S. Pat. No. 3,941,237 has a relatively narrow tolerance with respect to the outside diameter of an aerosol container. It has also been found that the relatively narrow tolerance range of the known puck is due to an integral molding of the shell and the fins to given dimensional levels that are compatible with only a single type of container from a single commercial source.
Since there are various different sources for aluminum containers, the outside diameters from source to source usually vary in the range that extends beyond the tolerance range of the known puck. Thus it may be necessary to allocate different sets of pucks for each different source of aerosol containers to ensure compatibility between the puck and the container.
A desirable match between puck and container does not cause excess interference between the fins and the periphery of the container. Since an empty aluminum aerosol container is easily deformed, excess interference between the puck and the container will damage or mar the container upon insertion into the puck. If interference between the puck and container does not exist or is too slight, the container is likely to float in a water bath that is used during the container cleaning process.
Thus, an inventory of pucks which are compatible with the containers of one manufacturer and incompatible with the containers of another manufacturer may limit a processor to a single source of aluminum containers. The alternative is to maintain enormous puck inventories with slight dimensional variations to accomodate dimensional variations in the containers of different manufacturers.
A processor is thus burdened by enormous space demands and cataloguing requirements in order to maintain puck inventories that respond to the dimensional variations of containers that are characteristic of different manufacturers. The expense of acquiring and organizing puck inventories which assure compatibility with containers furnished by various manufacturers increases product costs and ultimately reduces overall sales and profits. Furthermore, there is considerable disruption of a production line when puck changes are required during a production run to accommodate aluminum containers that are obtained from more than one vendor.
It is thus desirable to provide a holding device for containers that is more forgiving of dimensional variations in containers from different sources than the known puck. It is also desirable to provide a holding device that can be adjusted or modified to accomodate containers of different size.